Chronic pain remains a major burden on society, significantly affecting millions of people and costing the populace billions annually. Despite major advances made to our understanding of pain, very few novel therapies have successfully translated to clinical care. A particular shortfall in this translation is due to the lack of a reliable, high-throughput, commercially available in vivo assay in rodents, particularly in mice. To address this deficit, we propose an innovative, automated, operant behavioral approach for assessing pain in rodents, with our long-range goal being the establishment of an operant model system that will quickly, systematically, and effectively evaluate pain. The central hypothesis is that operant assays can provide a sensitive, reliable, and clinically relevant way to evaluate sensory and nociceptive processing. One specific aim will be investigated: to evaluate a mouse operant model of thermal hyperalgesia and allodynia as compared to the rat operant model for studying pain. We will test this aim using an extremely innovative, automated, high-throughput approach for testing pain and analgesia in mice and rats. This includes using a reward-conflict strategy for assessing thermal pain. The rationale for the proposed research is that use of these operant assays in rats and mice to evaluate pain will provide a better method for future investigation of the mechanisms underlying pain disorders. This study explores an innovative approach for evaluating animal models of pain and would significantly advance the development of new treatments by providing a quick and reliable pain testing system using rodents. The product and process to be developed is an automated, user-friendly, investigator-independent, high-throughput, in vivo pain and analgesic testing system. We are particularly well-suited to complete this body of work, given the pairing of Stoelting Company's expertise in developing the product and Drs. Neubert and Caudle's pain-research experience. This line of research is significant because it explores a novel, high-throughput method to assess pain and pain relief following analgesic administration. If this line of research is successful, the result will have a significant impact on the way new pain-relieving therapies are screened and evaluated, ultimately allowing for a great reduction in the time for new drugs to become available clinically. [unreadable] [unreadable] [unreadable]